Gear-cutting machine with safety-stop



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U., H. E. an P. L. BBERHARDT. GEAR CUTTING MAGHNE WITH SAFETY STOP.

No. 575,393; Pamted Jan. 19, 1897".

| Uli Ml" l l1 (No Modell) Y 4 Sheets-Sheet 2. U., H. E. 8E F. L EBERHARDT.

GEAR CUTTING MACHINE WITIT sIIIIzTIIV STOP. I No. 575,393. PatentedJan. 19, 1897.

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(No Model.) 4 4 Sheets-Sheet 3. U., H. E. 8v P. L. EBERIIARDT. GEAR CUTTING MACHINE WITH SAFETY STOP.

Patented Jan. 19, 1897.4

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I GEAR CUTTING MAGHINE WITH SAFETY STOPg' No. 575,393. Patented Jan. 19,1897.

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ATRNT OFFICE.

HENRY E. EBERHARDT, AND FRED L. EBERHARDT,

OF NEWARK, NEWr `JERSEY.

GEAR-CUTTING MACHINE WITH SAFETY-STOP.

SPECIFICATION forming' `part 0f Letters Patent NO. 575,393, dated. January 19, 1897'.

Application tiled Jun@ 9, 1896. Serial No. 594,827. (No model.)

useful Improvements in Gear-Cutting Ma` chines with Safety-Stops, fully describedand represented in the following' specification and io the accompanying drawings, form ng a part of the same.

The present invention relates to that class of `gear-cutting machines in which the driving-pulley is rotated continuously and operi ates intermittingly and automatically upon a train of change-wheels to turn the blank into successive positions for cutting a series of teeth therein, and in which the chan ge-wheels are sometimes connected directly with the cutzo ter-spindle, so as to rotate the same in unison with the blank when hobbing7 or cutting worm-teeth in the same. In this class of machines the cutter is reciprocated to and from the blank by a cutter-head actuated by a feed- `2 5 screw with suitable clutch mechanism to rcverse its rotations automatically, and the present invention furnishes a safety-stop to hold such clutch mechanism in a neutral or inoperative position until the blank is prop- 3o erly rotated, and thus avoid the cutting of the same at an improper point.

The inventionalso furnishes an improved connection between the change-wheels and the cutter-spindle for use in hobbing, a sin- 55 gle shaft being connected by detachable gear directly with the change-wheel arbor and the cutter-spindle, the arrangement being such as not to interfere with the operation of the safety-stop when cutting spur-gears.

The invention will be understood by reference to the annexed drawings, in which- Figure 1 is a plan of a gear-cutting machine with certain Well-known parts omitted which are not required to illustrate the invention. Fig 2 is a side elevation of the same; Fig. 3, an end elevation of the feedclutch shifter; Fig. 4, a plan of the stopshaft and its attachments. Fig. 5 is a diagrainmatic elevation of the same upon the in- 5o ner side; Fig. (i, a front view of the same;

Fig. 7, a diagram of the stop-wheel with grooved cani to control the pawl; Fig. 8, a

`ent No. 510,122,

vertical section of the hobbing connections for the cutter-spindle, and Fig. 9, a longitudinal section of the gear-box for the hobbilig-shaft. Fig. 10 is a front elevation of t-he drop-lever n, with the adjacent end of the gear-casing N4, the shifter-arln g2 and the latch q' being relnoved and the reverse position of the trip-lever being indicated in 6o dotted lines. Fig. 1l is a plan of part of the casing N4, with the addition of the shifterarm and latch. Fig. 12 is a front View, and Fig. 13 an edge view of the shifter-arm g2 detached. Fig. 14 is a section of the entire 65 cutter-spindle with the cutter u and gearwheel nf.

The improvements are illustrated upon a machine resembling that shown in the Patgranted December 5, 1893, 7o to Ulrich Eberhardt, Henry E. Eberhardt, and Fred L. Eberhardt.

A designates the bed of the gear-cutter frame, and D a carriage Ior cutter-head tted to Ways upon the top of the bed. The cutterhead is provided, as Vshown in Fig. l, with a central opening to receive the cutter u, at the opposite sides of which are bearings Y for the cutter-spindle Y. A feed-screw a is secured to the carriage D and projected through 8c a rotary nut b, mounted in bearing b at the outer end of the hed, and provided with a feed-gear c at its outer end. The gear c is driven automatically in opposite directions lby two trains of gearing connected with a feed-shaft L, which is driven by a shaft J,

mounted at the rear end of the bed With a pulley J2 thereon.

The clutch-hub c', which connects the two trains of gearing alternately with the rotary 9o n ut b, (through the gear 0,) is shifted, as shown in the before-mentioned patent, by aclutchfork g, which is mounted upon shaft g', having upon its outer end a shifter-arm g2. This reversing-gearing for the feed-screw, with its clutch mechanism, is inclosed in the casing N4, from one side of which the shaft g projects to receive the sliifteiarm. A stud q is projected from the top of the arm g2, and a hook or latch q is pivoted upon the casing N4 roo adjacent to such arm and so adjusted to the stud that when hooked thereon it holds the clutch-fork in a central position Whenrequired to prevent the operation of the feeding devices. A trip-lever n is pivoted upon the shaft g and shifted by the carriage D through the agency of the shifter-arm g2. The shifter-arm is oscillated by the stop-rod P and dogs P', actuated by a lug P2 upon the carriage. The trip-lever n is provided with a l radial spring-bolt l, having wedge-shaped face adapted to operate with a stationary wedgeblock l to shift and hold the trip-lever alternately at opposite sides of its central position in the usual manner. The trip-lever is provided with lugs n to press upon opposite sides of the shifter-arm g2, the space between the lugs being made wider than the arm, as shown adjacent to the right-hand lug in Fig. 3, to permit the bolt to move past the center of the wedge Z' before the clutch becomes engaged, thus securing the engagement of the clutch, as is common in such reversing' operations.

The latch q is omitted from Fig. l to avoid obscurin g the trip-lever and shifter-arm,l but is shown in Fig. ll in the same position as in Fig. 2, engaged with the stud q upon the shifter-arm, to hold the clutch-fork in a central and inoperative position. Figs. l0 to 13 show the construction of these parts upon a larger scale than the other figures.

E' designates the column carrying the 1nan drel-head F, provided with the mandrel-shaft G, having upon its outer end a worm-wheel H. The pulley J2 is connected by gears K and' friction device I2 wit-h the worm I to rotate the mandrel A and the blank intermittin gly.

It will be understood that the friction device or disk I2 is fastened, as is common in such machinesto the shaft upon which it is` H'. rlille-frame G supports a bracket G2, upony which are mounted the stop-shaft S and an adjustable stud S for carrying intermediate change-wheels S2. The worm-shaft I is connected. with the stop-shaft S (through the interm edi-ate wheels S2) by the change-wh eels I3.

The bracket Ggand allotl the stopinechanism are shown in detail in Figs. et to.7, inclusive,4 but the bracket andthe bearings upon the-saine .are indicatedonly by dottedlines in Fig. 2, so as to exhibit clearly the parts in the rear ofthe same.

A" casting, as shownin Figs. 4 and 6, is secured-upon the bracket G2 and provided with bearing C for the stop-shaft, bearing C for the stopfpawhand bearing C? for the pawldetentf.

Af, stop-disk d is formed with circular peripheryvhaving al notch d in the edge and secured upon the stop-shaft with a cam d2 at one side of the same. The stop-pawl is provided with a tooth e to engage the edge of the notch d and with an arm f to engage a cam` for pressingthe tooth into the notch. The pawl serves, normally, by engagement with the side of said notch, to intermittently regulate the rotations of the change-wheels to shift the blank through a definite angle, and the detent t is connected by an adjustable chain p with the lug P2 upon the cutter-head D to pull upon the detent and draw the pawl from the notch d at each outward stroke of the cutter-head. The detent is fitted movably by a shank to a pivoted arm h3, which is drawn backward, normally, by a spring 7L' and is provided with an eye h2 to receive the chain or rod for pulling the detent. The eye h2 is omitted from the arm h3 in Fig. 5, as the latter ligure is designed simply to illustrate the coaction of the deten t, the pawl, and the stop-disk. As the change-wheels perform their entire function during one rotation of the stop-disk, it is essential that the pawl should be released by the detent before such rotation is completed, and such release is effected by forming a cam-shaped groove in the periphery of the disk and projecting a toe 't' from the pawl into such groove, the bottom of which is extended to the edge of the disk, so as to force the detent upwardly and release the pawl as soon as the disk has made a partial rotation. The detent is thus wholly cleared from the pawl. and the latter left free to engage the notch d before such notch can by any possibility be turnedk past the pawl'. The detent when disengaged from the arm is pressed outwardly by a spring beneath the shank to aY suitable point to catch` upon the tip of the pawl, as shown in Fig. 7, being pressed inwardly to slip over the top of the pawl, as shown in Fig. 5, when the tension upon the eye h2 is released and the detent is drawn backward by the spring 7L. The pawl is also provided with an arm e', connectedA by link M with a loose collar m upon a stop-rod N. The rod N is mounted vertically at the side of, the column E in bearings N and N2, and a stop-slide 0 is fitted to bearings at the side of the bed and connected by a rod or link o with the clutch-shifter arm g2.V

The slide o is arranged beneath the stoprod N an d provided witha projection or block o2, which bears against the sideof the stoprod when the shiftenarm is in the central position and the feed-clutch.inoperative. Une of the trains of feed-gearing is so arranged that the stop-rod must be raised to permit the movement of the slide 0 before the clutch can be engaged to feed the cutter forward after each shift of the blank.

The cutter-head D is shown in Fig. 2 at the end of its outward stroke in readiness to feed forward, and its previous outward movement shifts the trip-lever n a little past its central position, as shown in Fig. 2, in -readiness to automatically push the shifter-arm g2 in the IOO IIO

same direction (under the pressure of the spring-bolt Z) When the shifter-arm is released from thel restraint of the slide o. A spring n2 is fixed to the bracket G2 and the link M to press the stop-rod norm ally upward by contact with a dog m upon the same. As the paWl is governed by the notch in the disk d, t-he stop-rod can only be lifted and the slide o released when the paWl is resting Within said notch. A cam d2, (shown in Figs. 2 and 5,) Which covers a section only of the circle, operates upon the arm f when the paWl approaches the notch cl', as shown in Fig. 5, and the pavvl is at other times supported by its connection With the rod N, whichis then resting upon the slide 0.

'When the motion of the stop-disk is, by any defective operation of the mechanism, arrested before its completion, its circular periphery prevents the paWl, as shown in Fig. 5, from moving toward the stop-shaft, and the stop-rod then prevents the movement of the clutch-shifter, as desired.

Then the stop-disk is normally rotated, as shown in Fig. l, the arm c lifts the stop-rod N to clear the corner of the block o2, and the slide is then moved laterally, as indicated in dotted lines in Fig. 2, by the operation of the spring-bolt Z upon the shifter-arm g2. Such motion clutches the nut b to the proper train of gearing and propels the carriage forward into the blank until its movement is reversed by the dog P. (Shown in Fig. l.)

A slightlydiiferent cam connection is shown in Fig. 7, Where the paw] is provided with an arm j", havinga pin iitted to a groove cl3 in the face of the stop-disk d, such camgroove holding the pawl adjacent to the edge of the disk and pulling the tooth at the required time into the notch d to arrest the disk. )Vith this construction it is obvious that the entire motion of the paWl is effected by the cam connection, and that the paWl is therefore more positive in its action than When moved in one direction bya Weight or spring.

Either of the cam connections operates to force the tooth e positively into the notch d' as the notch turns toward such tooth. The cam is so shaped adjacent to the notch CZ as to permit the movement of the arm With the pawl, when the detent is pulled to detach the pawl from the notch CZ near the outer end of the cutter-heads motion, which permits the change-Wheels to rotate the blank before the cutter-head is fed forward. The essential feature of this part of the invention consists in the positive movement of the pawl by means of a cam rotated with the stop-disk to force the paWl-tooth into the notch upon the disk, and thus absolutely prevent the disk from rotating past the desired point. In machines of this class the Worm-shaft I and the change-Wheels are rotated by friction-gearing, which continues to actuate such Wheels and to rotate the blank until their motion is arrested by the stop mechanism, and this de- Vice secures positively the checking of such motion when the blank has been rotated through the required arc. The stop-rod and its control by the position of the paWl which holds the clutch in a neutral position until the stop-disk is fully7 rotated also positively secures the clutch from movement until the disk is fully rotated, and the intermittent movement of the blank is thus effected With absolute certainty.

The form of the cam which moves the paWltooth into the notch upon the stop-disk is immaterial, as also the precise construction and arrangement of the stop-rod which connects the paWl detachably with the clutclrshifter.

Itis very desirable that machines of this class should be provided with a direct con.

nection between the Worm-shaftI and the cutter-spindle Y, so that they may be adjusted to rotate in unison When hobbing or cutting Worm-teeth upon the blank. The present construction is therefore provided with such a hobbing attachment, the hobbing-shaft t being shown in Fig. l connected With the stopshaft S, and the spindle Y provided with a hob or Worm-cutter n'. -A bearing u for the shaft t is fitted by a swivel-collar o to the stop-shaft and the shafts are connected by bevel-gears t2, and the shaft is iitted to slide longitudinally through a bearing V, Which is sWiveled upon a stud x', attached to the cutter-head D, adjacent to the spindle Y. A part only of the shaft t (with the bearing V) is shown in Fig. 2, so as not to obscure the safety-stop mechanism.

A gear-Wheel tu is secured to the outer end of the spindle Y, and an auxiliary gear-Wheel .w' (meshing therewith) is fitted to the stud tt, and bevel-Wheels m2 connect the Wheels to with the hobbingshaft t, which is iitted by a splined joint at to the Wheel wz, through which it passes, such Wheel, as shown in Fig. 9, being furnished With a sleeve to rotate in the bearing V. A key is secured removably in the sleeve and is fitted to a keyway in the shaft t, thus forming the splined joint v to rotate the bevel-Wheel With the shaft when required.

)Vhen the hobbing device is not required for use, the key 0c may be removed, thus permitting the hobbing-shaft to rotate Without affecting the cutter-spindlerlhe wheel to2 may, if preferred, be made detachable from the cutter-spindle, as it is immaterial what gearwheel lbe removed or rendered inoperative to disconnect the hobbing-shaft and spindle. The bearing is provided With a casing V to incloseA the Wheel wz and is swiveled to the stud u by means of a shank a9', which is projected from the casing through the stud and secured upon the inner end of the latter by a screw and Washer ft2. The stud is shown connected by bracket X With the bearing of the cutterspindle, but itis immaterial hoW the stud or auxiliary wheel be supported.

The hobbing-shaft is connected With the auxiliary Wheel tu instead of with the Wheel TOO IIO

w upon the cutter-spindle to permit the manipulation of the cutter-spindle Y, Which is required in applying and removing various kinds of cutters, so formed upon the top as to permit the withdrawal of the spindle Y with the gear-wheel w When it is necessary to change the cover or hob upon the spindle. The wheel w is shown fitted removably upon the end of the spindle, so that it may be removed when the hobbing attachment is'not in use, and the gear thus forms a direct detacha-ble connection between the cutter-spindle'and the hobbing-shaft- Ve have made special claim herein to a cam-groove rotated with the stop-disk and a projection from the pawl fitted to such groove, so as to-e'ffect the entire motion of the pa-wl by the cam, as such construction secures al positive action of the safety-stop device, andl obviates any .of the uncertainty that exists in the' use of weights or springsto partially control the movement ofv the pawl.

From the above descriptionit will be understood that we do not vclaim a safety-stopfor the cutter-head of the gear-cutting machine, but the combination, with the other elements, of a stop-disk having a circular periphery with notch in the edge and a pawl which is adapted ence oi' the stop-rod N with the movement of the stop-slide, which is prevented from motion until the stop-rod is drawn wholly away from the block or projection 02 upon the slide. The feed is thus positively prevented from operating and the cutter from penetrating the blank unless the stop-disk is completely rotated and the-blank fully shifted into the required position for. operation.

We have made no broad claim herein .to a safety-stop upon cutter-head or gear-cutters, because such a stop has within our knowledge been used for twenty years past ina large machineshop, and such a safety-stop is not therefore patentable.

Although our device is intended to secure the same object, it operates with more certainty andis more simple in construction than anything that has within our knowledge been previously used for the same purpose.

Having thus set forth the nature of the invention, what is claimed herein is,-

l. In agear-cutter, the combination, with a cutter-head and reversing-gear having a clutch-shifter, of change-wheels and a stopdisk rotated thereby, and havinga circular periphery with notch in the edge, and a pawl suitably connected tothe clutch-shifter and provided with a tooth to engage the notch, and adapted to rest upon the circular periphery of the stop-disk, and to thereby hold the clutch-shifter in a neutral position throughout the entire rotation of the disk. until the tooth enters such notch, substantially as herein set forth.

2. In a gear-cutter, the combination, with a cutter-head and reversing-gear having a clutch-shifter, oi change-wheels and a stopdisk rotated thereby, and having circular periphery with notch in the edge, a pawl suit: ably connected to the clutch-shifter and provided with a tooth to engage the notch and with the arm f, and a cam rotated with the stop-disk and adapted by pressure upon the armv to force the pawl-tooth into the said notch to positively arrest the disk, substantially asset forth.

3. In a gear-cutter, the combination, with a cutter-head and reversinggear having a clutch-shitter, of change-wheels and stop-disk rotated thereby and having circular periphery with notch d in thel edge, a pawl with tooth to' rest upon the edge of such disk and engage the notch, and a stop-rod controlled by said pawl, and a slide linked to the clutch-shifter and having aprojection tofengage the stoprod, the whole arranged and operated substantially'aS-herein set forth.

4; In a gear-cutter, the combination, with a cutter-head and reversing-gear having a clutch-shifter, of the mandrel-head F with change-wheels and stop-disk carried thereby, a vertical stop-rod supported adjacent tothe stop-disk, a horizontal slide connected with the clutch-shifter and provided with a projection to engage the stop-rod, a pawl iit'ted to bear upon the edge of the stop-disk, a loose collar upon thestoprod and a link to move thevsame with the pawl, and an adjustable dog upon the stop-rod to contact withv the loose collar in various positions of the mandrel-head, substantially as herein set forth.

5. In a gear-cutter, the combination, with a cutter-head and reversing-gear having a clutch-shifter, of ythe mandrel-head F with change-wheels and stop-disk carried thereby, a vertical stop-rod'supported adjacent to the stop-disk, a horizontal slide connected with the clutch-shifter and provided with a projection to engage the stop-rod, a pawl iitted to'rbear upon the edge of the stop-disk, a loose collar upon the stop-rod, a link to move the same with the pawl, an adjustable dog upon the stop-rod to contact with the loose collar in various positions of the mandrel-head, and a spring applied to thel link to balance the same and normally lift the stop-rod, as and for the purpose set forth.

(5. In a gear-cutter, the combination, with the bed A, column E, and mandrel-head pr0 vided with frame G' carrying the worm-spindle I change-wheels and stop-shaft S, of cutter-head D provided with cutter-spindle Y, and a single hobbing-shaft connected at its IOC IOS

IIC

opposite ends by suitable gearing to the con` tiguous ends of the stop-shaft and cutterspindle, substantially asset forth.

7. In a gear-cutter, the combination, with the bed A, column E, and mandrel-head provided With frame G/ carrying the worm-spindle I change-Wheels and stop-shaft S, of cutter-head I) provided with cutter-spindle Y, and a stud adjacent to the spindle, a gear upon the spindle and an auxiliary gear upon the stud, and a hobbing-shaft connected with the stop-shaft and with the auxiliary gear upon the stud by swivel-bearings and bevel-gears, substantially as herein set forth.

S. In a gear-cutter, the combination, with a cutter-head and reversing-gear having a clutch-shifter, of change-Wheels and a stopdisk rotated thereby and having notch in the edge, a paWl suitably connected to the clutchshifter and provided with a tooth to engage the notch, a detent pivoted adjacent to the paWl and provided with a spring-shank, a connection from the detent to the cutter-head to pull the detent, and a cam rotated With the stop-disk and operating upon such detent to detach it from the paWl before the disk has completed one revolution, substantially as herein set forth.

9. In a gear-cutter, the combination, with a cutter-head and reversing-gear having a 30 clutch-shifter, of change-Wheels and a stopdisk rotated thereby and having circular periphery With notch in the edge, a paWl suitably connected to the clutch-shifter and provided With a tooth to engage the notch, a cam- 35 groove rotated with the stop-disk, and a projection from the pawl to engage such groove, the entire motion of the paWl being eected by such cam, and the clutch being thereby held in a neutral position until the disk is 4D ULRICH EBIEIRHARDT.` HENRY E. EBERHARDT. FRED L. EBERI-IARDT.

I/Vitnesses:

THOMAS S. CRANE, HENRY J. RUEscH. 

